The present invention relates to a method and system for determining pupillary distance and multi-focal element height for prescription eyeglasses via images received through a computer network.
In the United States, the market for ophthalmic goods such as glasses and contact lenses is estimated to exceed over sixteen billion dollars. As with other retail markets, the leaders in providing eyeglasses have recently begun to move retail sales to the Internet in order to expand their market share. Consumers have benefited from the move by having access to a wider selection of frames at a cheaper price than can usually be obtained at a bricks and mortar retail store.
Unfortunately, sales of prescription eyewear over the Internet are limited because users are unable to actually try on frames before purchasing. In an effort to overcome this limitation, some retail eyewear providers operating on the Internet have utilized methods to xe2x80x9cvirtuallyxe2x80x9d try on different frames through their web sites. In order to accomplish this, users will submit an electronically formatted image of their face to the retailer. The image can be created by using a digital camera or camcorder, by scanning in a conventional photograph, or through any other known technique. The submitted facial image is then stored on the retailer""s server and is associated with a particular client for all future transactions.
Once the facial image is stored on a server, software programs known in the art can combine the photograph with stored images (or some type of image definition) of eyeglass frames. The user is then invited to select a pair of frames to xe2x80x9ctry on.xe2x80x9d Once the pair is selected, the stored facial image is superimposed with an image of the selected frame. This combined image is then presented to the user so that the user sees their own image wearing the selected frame.
This xe2x80x9cvirtual try-onxe2x80x9d technique should greatly assist Internet retails sales of prescription eyeglasses. However, the loss of the ability to try on glasses is only one of the disadvantages working against eyewear Internet sales. A second disadvantage is that most ophthalmic goods require a prescription indicating the vision correction required by the individual purchaser. As a result, web sites providing eyeglasses to customers must ask for specific prescription information.
One help to e-commerce in this area is that the Federal Trademark Commission (or FTC) has developed a xe2x80x9cprescription release rulexe2x80x9d that requires eye doctors (including both optometrist and ophthalmologists) to give their patients an eye glasses prescription immediately after an eye exam. By rule, this prescription must include the sphere, cylinder, and axisxe2x80x94the three components that determine the prescription needed to correct vision. The rule was enacted to ensure the patients would be free to shop for eyeglasses at locations other than their eye doctor""s office. Prior to the rule, patients were often unable to obtain their prescriptions and as a result were only able to order lenses through their eye doctor, or were forced to see the eye doctor at their preferred retail location.
As a result of this rule, most individuals in the United States who require vision correction have easy access to their prescription. This has made it easier to purchase eyewear on the Internet, as the web site can simply request that users enter the information found on their prescription card. Unfortunately, one crucial element needed for grinding eye glass lenses usually is missing from the prescription provided by eye doctors under this rule, namely the pupillary distance (or, more accurately, xe2x80x9cinter-pupillary distancexe2x80x9d). This distance is the measurement from pupil to pupil, and is required to properly grind lenses for a particular set of frames.
Prior to Internet retail web sites, this was not a significant issue since any retailer could take the pupillary distances (or xe2x80x9cPDxe2x80x9d) measurement upon examining the patient. With Internet sales of eye wear, it is impossible to obtain the PD measurement through direct measurement of the patient. At the present time, web sites must simply ask for the end user to provide the pupillary distance, just as the site asks for the vision correction prescription. Because the measurement is not found on the typical prescription card provided by the eye care professional, the web site must explain to the end user what is meant by pupillary distance. The site must then either advise users how to have this distance measured and recorded for them, or how to mark their own pupils on a mirror and measure the PD by measuring the distance between the marks.
Unfortunately, many customers are scared off by either having to measure the pupillary distance themselves or by contacting the bricks and mortar retailer that they hoped to avoid by shopping over the Internet. What is needed is a way to purchase prescription eyewear over the Internet that requires users to provide only the basic prescription information generally found on the optical prescription card provided under the FTC rules.
The present invention meets these needs by determining the pupillary distance for a user from an image provided for use with xe2x80x9cvirtual try-onxe2x80x9d technology. This is accomplished by having the user place a reference object on or near their face in the virtual try-on image. The reference object should be one that is a standard size and is readily available to users. One example for the U.S. market is a U.S. quarter dollar. Alternatively, the reference object used can be the iris in a user""s own eye, since it is well known that the human iris is of a relatively fixed size from individual to individual.
When using a reference object, the user takes the facial picture with the reference object on generally the same plane and distance from the camera as their face, such as by holding a quarter on their chin with a single finger. The image is then submitted to the web site as is now standard with sites utilizing virtual try-on technology.
After the image is transmitted, the image can then be resized and used to try-on different frames as is known in the prior art. Alternatively, a second image without a reference object can be used for trying on frames.
Once the frames are selected and an order for the frames placed, the image with the reference object is associated with the order. The width of the reference object on the image is then compared to the measured pupillary distance on the image. These measurements can be made in pixels as opposed to real-world distances, because the image is being provided in a pixelated digital file. The actual pupillary distance can then be calculated by comparing the ratio of the distances measured in the image with the known width of the reference object.
Similarly, the virtual pupillary distance or segment height (usually called xe2x80x9cseg heightxe2x80x9d) needed for multi-focal elements can be determined by measuring the height using the frame on face virtual try-on technology. The measured distance on the image is converted to a real world measurement using the ratio obtained from the reference image.